1. Field of the Invention
The present invention relates to a zoom lens suitable for a single-lens reflex digital camera, a film camera and a video camera, an imaging apparatus equipped therewith, and a method for manufacturing the zoom lens.
2. Related Background Art
A zoom lens having a wide angle of view has been proposed in such as Japanese Patent Application Laid-Open No. 2004-21223. Regarding such a zoom lens having a wide angle of view, request for suppressing ghost images and flare, which deteriorate optical performance, as well as aberrations become increasingly strong. Accordingly, a higher optical performance is required to antireflection coatings applied to a lens surface, so that in order to meet such request, multilayer design technology and multilayer coating technology are continuously progressing (for example, see Japanese Patent Application Laid-Open No. 2000-356704).
However, in a conventional retrofocus type zoom lens described above, in order to improve optical performance, there has been a tendency that composition of the rear lens group becomes complicated and the number of lens elements increases. Moreover, since the rear lens group has been generally a so-called modified triplet type or an Ernostar type including a lens with strong negative power, decentering susceptibility tends to become high, so that assembling the lens system has been difficult.
Moreover, in a conventional zoom lens for a 35 mm format camera having a wide angle of view, since the diameter of the front lens is well exceeding a commonly used filter size. Moreover, when the angle of view of the zoom lens is made to be wider by using a conventional technique, the zoom lens may become a one having serious defects in astigmatism, curvature of field, coma and distortion. In addition, there is a problem that reflection light producing ghost images and flare is liable to be generated from optical surfaces in such a zoom lens.